Fluid moisture indicator



Feb. 25, 1964 w. c. YOCUM 3,122,124

FLUID MOISTURE INDICATOR Filed April 10, 1962 Fig.3 Fig. 4 INVENT I William C. Yoc

BY M 6mm H/S ATTORNEYS United States Patent This invention relates to a fluid moisture indicator and particularly to a liquid moisture indicator which is installed in pipe and conduit systems for detection of a change, particularly an increase, in moisture content of the liquid traversing the system and detection of leakage of the liquid therefrom is important. It has special utility for refrigeration systems which use liquid refrigerants. As used in this application, the term fluid applies to a gas or a liquid.

Maintenance of a low moisture content irl refrigeration systems which use liquid refrigerants is extremely important because presence of excessive moisture causes components of the system such as capillary tubes, expansion valves, etc. to freeze up with resultant erratic and faulty operation of the equipment. Accordingly, it is highly de sirable to employ moisture content indicators in the systems to detect a change, particularly an increase in moisture content of the refrigerant.

Discovery of a change in moisture content is achieved by use of moisture indicator elements which change color, such as from green to pink or from blue to pink, when the moisture concentration of the fluid exceeds a certain amount. These elements are chemicals and examples thereof are described in US Patents 2,761,312 and 2,836,- 974.

A large number of refrigeration systems use one of a number of refrigerants such as those identified as R11 (trichloromonofiuoromethane), R12 (dichlorodifluoromethane), R22 (monochlorodifiuoromethane), R40, R113, R114 and R500, with R12 and R22 being more frequently used than the others. Regarding refrigerants, R12 and R22, each has a difierent range of moisture content, the upper limit of which should not be exceeded for recommended operation of the refrigeration system containing same. A a result, R12 uses one moisture indicator element and R22 uses a second different moisture indicator element (described in US. Patents 2,761,312 and 2,83 6,974) to ascertain when the upper lhnit of the range of moisture content is exceeded so that steps can be taken to reduce the moisture content in the refrigerant. The moisture indicating element for R12 can also be used for refrigerants R11, R113, R114 and R500, and the moisture indicator element for R22 can also be used for refrigerant R40.

When the fluid moisture indicators are manufactured, it is not known in many instances whether a particular indicator will be used in a refri eration system which has the R12 or the R22 refrigerant. Accordingly, some indicators are made with both R12 and R22 moisture indicator elements mounted therein to reduce inventory requirements of suppliers and to simplify manufacture. However, when installing and using these two element fluid moisture indicators, problems arise from a standpoint of which moisture indicating elements should be observed and even of which refrigerant reverses the system into which the indicator has been installed. Unless the system is marked to identify the refrigerant therein or a serviceman knows or remembers the particulu refrigerant therein, confusion occus when inspecting the fluid moisture indicator to ascertain whether the moisture content has exceeded a specified amount. This is particularly true where both elements are exposed and further confusion results from uncertainty as to which colors should be used in determining whether the moisture content is at a proper level.

Most indicators have a sight glass or lens for observation of the element or elements and of the liquid refrigerant to determine presence of bubbles which indicate a leak in the system. This sight glass must be sealingly mounted in the indicator to prevent leakage of the refrigerant from the system and entry of air into the system. Additionally, it is desirable that the sight glass be mounted in a compression seal on its underside, around its side periphery and along the periphery of an upper part because glass under compression is strong and well able to withstand changes in pressure and temperature and to survive shock should the indicator be inadvertently dropped. Also, mounting of the sight glass under compression reduces generation of stresses which can result in fracture thereof.

My invention in fluid moisture indicators avoids confusion as to which refrigerant is in a system and which moisture indicator element of two or more in one indicator should be considered for ascertainment of whether the moisture content of the refrigerant is at a desired amount. Additionally, my invention permits easy observation of the fluid flowing through the system and pro vides a compression seal for the sight glass on its underide, around its side periphery and along the periphery of an upper portion thereof. Specifically, my invention resides in a fluid moisture indicator which has a body with a passageway for fiow of fluid therethrough and has interior surfaces defin ng a cavity having an opening at the top of the body and an intersection with the passageway and being above the passageway for mounting a lens. This lens is disposed in the cavity so that a substantial part of its top surface is exposed and so that the underside of the sight glass forms a part of the passageway.

At least first and second moisture indicator elements are disposed at the underside of the sight glass and each element is substantially in alignment with a portion of the exposed top surface of the lens substantially adjacent a peripheral part thereof. The first element is made to indicate the moisture content of a first fluid traversing the indicator by colors and the second element is made to indicate the moisture content of a second fluid traversing the indicator by colors.

A first detachable cover or cap for the first element is disposed substantially over that part of the top surface of the lens in alignment with the first element and extending substantially over said element to cover same from observation by a viewer. Also, a second detachable cover or cap for the second element is disposed substantially over that part of t e top surface of the lens in alignment with the second element and extending substantially over the second element to cover it from observation by the viewer.

The first cap has indicia which identifies at least one of the second fluid and of the colors for indicating moisture content of the second fluid. The second cap has indicia which identifies at least one of the first fluid and of the colors for indicating moisture content of the first fluid.

The lens has an underside, side walls, at least an upper portion of which inclines inwardly in a direction extending from a lower outside part towards an upper central part thereof.

The cavity is defined by interior surfaces of the body which include a bottom surface for mounting the underside of the lens along its periphery so that a portion of the underside forms a part of the passageway. The interior surfaces further include side surfaces for mounting the side Walls of the lens. nese side surfaces have an upper portion which inclines in a direction extending from a lower part of the cavity towards an upper central part thereof. Finally, the interior surfaces include an upper surface located for mounting an upper part of the lens along its periphery so that a substantial part of its top surface is exposed.

interposed between and in engagement with the peripheral underside of the lens and the bottom surface of the cavity, between the side walls of the lens and the side wall surface of the cavity and between the upper surface of the cavity and the upper part of the lens is a gasket means made from a resilient material which forms a seal between the body and the lens. Preferably, the lens is mounted in a compression seal upon the gasket along the periphery of its underside, around its side walls and around its upper part.

The bottom surface of the cavity is positioned a distance from the top of the body such that the exposed top surface of the lens is substantially flush with the top of the casing.

ln theaccompanying drawings I have shown a preferred embodiment of my invention in which:

FIGURE 1 is a plan view of a fluid moisture indicator which incorporates my invention;

FIGURE 2 is a section view along the line 11-11 of FIGURE 1;'

'FIGUR 3 is an enlarged fragmentary side elevation view in section showing a portion of the body, gasket and lens of the indicator of FIGURE 1 before a crimping operation which mounts the lens in a compression seal in the body; and

FIGURE 4 is a view similar to FIGURE 3'showing the body, gasket and lens after the crimping operation.

Referring to FIGURES l and 2, the indicator comprises a body 1 made from forged metal such as brass with a longitudinal passageway 2 extending therethrough for flow of a liquid refrigerant through the indicator. Above the passageway 2 is a vertically positioned, substantially cylindrical cavity 3 defined by interior surfaces of the body and disposed for receiving and mounting a sight glass or lens 4. The bottom of the cavity interconnects with the passageway 2 so that a portion of the underside 5 of the sight glass forms a part of the passageway. The cavity has an opening 5 at the top of the body to expose a substanc'al part 7 of the top surface of the sight glass to an observer of the indicator.

Located in the passageway substantially opposite and spaced apart from the underside of the sight glass is a bailie or diverter 8 which projects from the bottom'of the passageway 2 towards its top and extends widthwise thereof. This diverter deflects the liquid flowing through the passageway from its entry end 2:: upwardly in the direction of arrow 9 towards a portion of the underside of the sight glass which is substantially opposite the exposed part 7 of the'top surface of the glass. The liquid next flows over and across the top surface of the diverter 8 and out the exit end 2b of the passageway. Thus, the diverter brings the liquid close to the underside of the sight glass to make easy observation thereof for presence of bubbles which indicate leakage of the liquid from the system of which it is a put.

The interior surfaces of the body 1 which define the cavity 3 include a bottom surface It: which is part of an interior ledge 11 of the body for seating the periphery of the underside 5 of the sight glass. This ledge defines an interconnection 12 of the cavity with the passageway 2.

The interior surfaces of the body further include side walls, a first portion 13 (FIGURES 2 and 4) of which extends substantially perpendicularly a distance from its intersection with the bottom surface Ill? and a second portion 1d of which inclines inwardly and upwardly from the top of the first portion 13 in a direction extending from a lower outside part of the cavity towards an upper central part thereof. Preferably, the amount of inclination of the second portion 14- of the side surface is from about l0 relative to its intersection with a vertical axis located parallel to the central vertical axis 15 of the body. The

second portion terminates at an intersection with an unercut surface 16 which is part of a circular lip 17 (FIG- .41 URES 2 and 4) of the body and which runs substantially parallel to the top surface of the body. The periphery of the lip defines the opening def the cavity at the top of the body.

Mounted in the cavity is-the sight glass 4 with a sealing gasket 13 interposed between the periphery of its underside 5, its side walls 19 and an upper shoulder 2d and the interior bottom, side and undercut surfaces of the cavity. As shown in FIGURES 2-4, the sight glass has on its underside a peripheral downwardly extending ring 21 which seats upon a bottom portion 22 of the gasket 18 disposed upon the bottom surface it) of the cavity. This bottom portion 22 of the gasket runs completely around the ring and the bottom surface it? of the cavity. Extending upwardly from the peripheral ring 21 are the peripheral side Walls 19 of the glass which include a first part 23 running from its intersection with the ring outwardly towards the top of the glass to a rib 24. A second part 25 of the side walls inclines or tapers from the rib 24 inwardly towards an upper part of the glass and towards its central vertical axis which corresponds to the axis 15 t0 the shoulder 29 close to the top surface of the glass. The amount of thetaper or" the side walls of the glass preferably is about l0 -30 relative to a vertical line disposed parallel to the central vertical axis of the glass.

interposed between the side walls 23 and 25 of the glass and the side surfaces 13 and 14 of the cavity is a side portion 25 of the gasket which extends peripherally completely around he side walls of the glass from the perip eral ring 21 to the shoulder 26 of the glass. The'gasket also has an upper portion 27 which is interposed between the shoulder 20 of the glass and the undercut surface 16 of the cavity. This upper portion 27 of the gasket ex tends completely around the shoulder 21 Thus, the gasket 18 effects three seals in series, namely, the one between the peripheral sting of the glass and the bottom surface of the cavity, the one between the side walls of the glass and the side surfaces of the cavity, and the one between the shoulder of the glass and the undercut surface of the cavity.

While the gasket shown is an integral one, it can be comprised of two or three segments, one for the bottom part, a second for the side part, and the third for the upper part. Materials from which the. gasket can be made include, but are not limited to, natural rubber, synthetic rubber, nylon, Teflon, polyethylene, urethane, polypropylene, and other suitable resilient sealing materials.

Referring to FIGURES 3 and 4, the sight glass is mounts the cavity upon the gasket to form a compression seal (shown in PIGUREA) by a crimping operation on a hydraulic press. FIGURE 3 shows a fragmentary portion of the body which forms the cavity before the crii ping operation with the gasket in place and the peripheral ring 2?. of the sight glass resting upon the bottom portion 22 of the gasket. indicator after the crimping operation in which the body is swag-ed until the sight glass is nestled in the compression seal in the cavity upon the gasket. In this compression seal, the si ht glass is under compression along the periphery of the ring 21, completely around its side walls 23 and 25 and around its shoulder 2b. In the crimping operation, the gasket is compressed against the glass and extrudes or flows along the bottom surface of the cavity from the position of FIGURE 3 to the position of PI- URE 4 and along the width of the shoulder as shown from a consideration of FIGURES 3 and 4. Thus, the compression seal is three seals in series, thereby making the indicator virtually leakproof.

in this compression seal, the shoulder 2d of the glass is under compressive force, the side walls and particularly the second portion 25 of the side walls, whereby the compressive forces generated by the crimping operation acts toward the center of the glass and forces it down tightly upon the bottom part 22 of the gasket. Accordingly, the glass is in a compression seal'on its underside,

FIGURE 4 shows the its entire side walls and completely around an upper peripheral portion, the shoulder 29, which is highly desirable for glass is strongest when under compression. Also, the sight glass under such compression is better able to withstand changes in pressure and temperature and shock and is not readily subject to stress which may fracture it.

The compression seal of the indicator has a particular advantage in that as the internal pressure in the system increases, the sight glass is more tightly wedged against the top seal and the upper side seal due to the disposition of the shoulder and the upwardly, inwardly inclining side walls and upper side surfaces 14. While the internal pressure has a tendency to move the sight glass away from the bottom seal as internal pressure increases, and while the bottom seal then becomes slightly less effective, the upper side and top seals become more effective to render the indicator virtually leakproof.

As shown in FIGURES 1 and 2, interiorly of the peripheral ring on the underside of the glass is an annular groove 28 on diametrically opposite sides of which is a first moisture indicator element 29 for refrigerant R22 and a second moisture indicator element St for refrigerant R12. The two el ments are maintained in engagement with the underside of the glass by a spring member 31 seated upon the diverter 8. The first element is in alignment with a first peripheral portion 32 of the exposed top surface 7 of the glass and the second element is in alignment with a second peripheral portion 33 of the exposed top surface of the glass, whereby each element is visible to a viewer of the indicator.

Disposed directly over the first element 29 and on the top exposed surface of the glass and covering it is a first detachable cap 34 with indicia which identifies the refrigerant R12 for which the second element 39 is made and with two color areas, blue 35 and pink 3-6. he color blue informs an observer that when the element is blue, refrigerant 12 has a satisfactory moisture content and the pink color advises the observer that when the element has that color, refrigerant R12 has an excessive moisture content. The blue area has the word Dry and the pink area the word Wet.

Disposed directly over the second element 39, the one for refrigerant R12, and on the top exposed surface of the glass and covering the element is a second detachable cap 37 which has indicia for identifying refrigerant R22 and two color areas, green and pink 3?. The color green informs an observer that when the element 29 is green the moisture content of refrigerant R22 is satisfactory and the pink color informs the observer that when the element 29 has that color, the moisture content of refrigerant R22 is excessive. \Vithin the green color rea is the word Dry and within the pink color area is the word Wet. Each cap has a snap fit for engagement with the exterior of the lip of the body.

When the indicators are installed in a system which uses refrigerant R12, the cap 37 is detached to uncover the element 3% made for refrigerant R12 and thereby exposes it for viewing by an observer of the indicator. The remaining cap 3 carries the indicia R12 and the two color areas blue and pink with the word Dry in the blue area and the word Wet in the pink area. Thus, an observer of the indicator learns which refrigerant is in the system and is informed of the colors which indicate whether the system is wet or dry. Correspondingly, when the indicator is installed in a system which uses or will use refrigerant R22, the cap 34 with the indicia R12 is removed to uncover the element 29 made for refrigerant R22, thereby rendering it viewable to an observer of the indicator.

The two detachable caps with the indicia set forth above on each and with each cap covering the element which is not to be viewed or considered in determining the proper moisture content of the system, avoids confusion as to which refrigerant is in the system and which color should be used to ascertain whether the moisture content in the system is at the desirable level.

In place of the caps I also use detachable covers such as pressure sensitive base decals one of which is peeled off when the indicator is placed in service.

To permit ease in viewing the refrigerant for presence of bubbles and to better observe the elements, the bottom surface of the cavity is positioned a distance from the top of the body such that the exposed top surface 7 of the sight glass is substantially flush with the top of the body. This is shown by FIGURES 2 and 4.

My invention in the fluid moisture indicator has important advantages in that it provides an indicator which is virtually lealrproof and which places the sight glass or lens under a compression seal so that the indicator is highly resistant to shocks which may generate stresses resulting in fracture of the glass. Also, the indicator is far better able to withstand changes in pressure and temperature.

in combination with the advantages of the above paragraph, the use of the detachable caps with the color areas and the indicia thereon and with their location such that they cover the element not relied upon for a particular refrigerant avoids confusion and error in ascertaining whether the moisture content of the refrigerant is at a desired level.

While i have shown and described a present preferred embodiment of my invention, it is to be understood that it may be otherwise embodied Within the scope of the following claims.

I claim:

1. In a fluid moisture indicator having a body with a passageway for flow of fluid therethrough and with interior surfaces defining a cavity having an opening at the top of said body and an intersection with said passageway and being above said passageway for mounting a lens and with a lens disposed in said cavity so that a substantial part of its top surface is exposed and so that the underside of said lens forms a part of said passageway, the invention comprising at least first and second moisture indicator elements disposed at the underside of said lens, each indicator element being substantially in alignment with a portion of the exposed top surface of said lens substantially adjacent a peripheral part thereof, said first element being made to indicate moisture content of a first fluid traversing said indicator by colors, said second element being made to indicate moisture content of a second fluid by colors, a first detachable cover for said first moisture indicator element disposed substantially over that part of the top surface of said lens in alignment with said first element and extending substantially over said first element to cover same from observation by a viewer, a second detachable cover for said second element disposed substantially over that part of the top surface of said lens in alignment with said second element and extending substantially over said second element to cover same from observation by said viewer, said first cover having indicia which identifies at least one of said second fluid and of said colors which indicate moisture content of said second fluid, said second cover having indicia which identifies at least one of said first fluid and of said colors which indicate moisture content of said first fluid.

2. In a fluid moisture indicator having a body with a passageway for flow of fluid therethrough and with inten'or surfaces defining a cavity having an opening at the top of said body and an intersection with said passageway and being above said passageway for mounting a lens, the invention comprising a lens having an underside, side walls at least an upper portion of which inclines inwardly in a direction extending from a lower outside part of said lens towards an upper central part thereof and an upper part, said interior surfaces defining said cavity including a bottom surface for mounting the underside of said sight glass along its periphery so that said underside forms a part of said passageway, including side surfaces for mounting said side WliiS of said glass, said side surfaces having an upper'portion which inclines inwardly in a direction extending from a lower part of said cavity towards an upper central part thereof and an upper surface located for mounting said upper part of said glass along its periphery so that a substantial part of its top surface is exposed, gasket means made from a resilient material and interposed between and in engagement with said underside and said bottom surface, said side W235 and side Wall surfaces, said upper surface and said upper part of said glass to form a seal between said body and said lens, said lens being in a compression seal upon said gask t dong the periphery of its underside, around said side Walls and around said upper part thereof.

3. The invention of claim 2 characterized by said bottom surface of said cavity being positioned a distance from the top of said body such that said exposed top surface of said sight glass is substantially flush with the top of said body.

4. The invention of claim 2 characterized by at least first and second moisture indicator elements disposed at the underside of said lens, each indicator element being substantially in ali nment with a portion of the exposed top surface of said lens substantially adjacent a peripheral part thereof, said first element being made to indicate moisture content of a first fiuid traversing said indicator by colors, said second element being made to indicate moisture content of a second fluid by colors, a first detachable cover for said first moisture indicator element disposed substantially over that part of the top surface of said lens in alignment with said first element and extending substantially over 'said first element to cover same from observation by a viewer, a second detachable cover for said second'elernent disposed substantially over that part of the top surface of said lens in alignment With said second element and extending substantially over said second element to cover same from observation by said viewer, said first cover having indicia W rich identifies at least one of said second fluid and of said colors which indicate moisture content or" said second fluid, said second cover having indicia which identifies at least one of said first'fluid and of said colors which indicate moisture content of said first fluid.

5. The invention of claim 4 characterized by said bottom surface of said cavity being positioned a distance from the top of said body such that said exposed top surface of said sight glass is substantially flush with the top of said body.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A FLUID MOISTURE INDICATOR HAVING A BODY WITH A PASSAGEWAY FOR FLOW OF FLUID THERETHROUGH AND WITH INTERIOR SURFACES DEFINING A CAVITY HAVING AN OPENING AT THE TOP OF SAID BODY AND AN INTERSECTION WITH SAID PASSAGEWAY AND BEING ABOVE SAID PASSAGEWAY FOR MOUNTING A LENS AND WITH A LENS DISPOSED IN SAID CAVITY SO THAT A SUBSTANTIAL PART OF ITS TOP SURFACE IS EXPOSED AND SO THAT THE UNDERSIDE OF SAID LENS FORMS A PART OF SAID PASSAGEWAY, THE INVENTION COMPRISING AT LEAST FIRST AND SECOND MOISTURE INDICATOR ELEMENTS DISPOSED AT THE UNDERSIDE OF SAID LENS, EACH INDICATOR ELEMENT BEING SUBSTANTIALLY IN ALIGNMENT WITH A PORTION OF THE EXPOSED TOP SURFACE OF SAID LENS SUBSTANTIALLY ADJACENT A PERIPHERAL PART THEREOF, SAID FIRST ELEMENT BEING MADE TO INDICATE MOISTURE CONTENT OF A FIRST FLUID TRAVERSING SAID INDICATOR BY COLORS, SAID SECOND ELEMENT BEING MADE TO INDICATE MOISTURE CONTENT OF A SECOND FLUID BY COLORS, A FIRST DETACHABLE COVER FOR SAID FIRST MOISTURE INDICATOR ELEMENT DISPOSED SUBSTANTIALLY OVER THAT PART OF THE TOP SURFACE OF SAID LENS IN ALIGNMENT WITH SAID FIRST ELEMENT AND EXTENDING SUBSTANTIALLY OVER SAID FIRST ELEMENT TO COVER SAME FROM OBSERVATION BY A VIEWER, A SECOND DETACHABLE COVER FOR SAID SECOND ELEMENT DISPOSED SUBSTANTIALLY OVER THAT PART OF THE TOP SURFACE OF SAID LENS IN ALIGNMENT WITH SAID SECOND ELEMENT AND EXTENDING SUBSTANTIALLY OVER SAID SECOND ELEMENT TO COVER SAME FROM OBSERVATION BY SAID VIEWER, SAID FIRST COVER HAVING INDICIA WHICH IDENTIFIES AT LEAST ONE OF SAID SECOND FLUID AND OF SAID COLORS WHICH INDICATE MOISTURE CONTENT OF SAID SECOND FLUID, SAID SECOND COVER HAVING INDICIA WHICH IDENTIFIES AT LEAST ONE OF SAID FIRST FLUID AND OF SAID COLORS WHICH INDICATE MOISTURE CONTENT OF SAID FIRST FLUID. 